REPORTING CSI WITH PHASE-COUPLING COEFFICIENTS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority to United States Provisional Patent Application Number 63/323,025 entitled “REPORTING INTER-TRP CO-PHASING COEFFICIENTS FOR COHERENT JOINT TRANSMISSION” and filed on 23 March 2022 for Roozbeh Atarius, which application is incorporated herein by reference. FIELD [0002] The subject matter disclosed herein relates generally to wireless communications and more particularly relates to techniques for reporting inter-Transmission-Reception Point (“TRP”) phase-coupling coefficients for coherent joint transmission (“CJT”) in Channel State Information (“CSI”) feedback. BACKGROUND [0003] A wireless communications system may include one or multiple network communication devices, such as base stations, which may be otherwise known as an evolved NodeB (“eNB”), a next-generation NodeB (“gNB”), or other suitable terminology. Each network communication devices, such as a base station may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (“UE”), or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers). Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (“3G”) Radio Access Technology (“RAT”), fourth generation (“4G”) RAT, fifth generation (“5G”) RAT, among other suitable RATs beyond 5G (e.g., sixth generation (“6G”)). [0004] In certain wireless communications networks, multiple transmission and reception points may be used. In such networks, channel state information may be transmitted by the multiple Transmission-Reception Points (“TRPs”). BRIEF SUMMARY [0005] Disclosed are solutions for reporting phase-coupling coefficients with CSI. Said solutions may be implemented by apparatus, systems, methods, and/or computer program products. [0006] One method at a User Equipment (“UE”) includes receiving a Channel State Information (“CSI”) reporting setting and receiving, from at least one of a plurality of network nodes (e.g., one or more TRPs), a Non-Zero Power CSI Reference Signal (“NZP CSI-RS”) associated with a channel measurement resource (“CMR”), where the CMR includes a plurality of CSI Reference Signal (“CSI-RS”) partitions. The method includes generating a CSI report based on the CMR. Here, the CSI report includes A) a plurality of Precoding Matrix (“PM”) values corresponding to the plurality of CSI-RS partitions, B) one or more sets of phase-coupling coefficients (also referred to as “co-phasing” coefficients) based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and C) an indication of a total number of coefficients of the plurality of PM values. The method includes transmitting the CSI report to at least one network node (e.g., at least one TRP) of the plurality of network nodes. [0007] One method at a Radio Access Network (“RAN”) includes transmitting a CSI reporting setting and transmitting a NZP CSI-RS corresponding to a CMR, where the CMR is associated with a plurality of CSI-RS partitions. The method includes receiving a CSI report based on the CMR, where the CSI report includes A) a plurality of PM values corresponding to the plurality of CSI-RS partitions, B) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and C) an indication of a total number of coefficients of the plurality of PM values. BRIEF DESCRIPTION OF THE DRAWINGS [0008] A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which: [0009] Figure 1 illustrates an example of a wireless communication system that supports techniques for reporting phase-coupling coefficients with CSI in accordance with aspects of the present disclosure; [0010] Figure 2 illustrates an example of a Third Generation Partnership Project (“3GPP”) New Radio (“NR”) protocol stack that supports different protocol layers in the UE and network in accordance with aspects of the present disclosure; [0011] Figure 3 illustrates an example of a UE served by multiple panels in a coordination cluster connected to a central unit in accordance with aspects of the present disclosure; [0012] Figure 4 illustrates an example of a UE transmitting a CSI report that contain a set of co-phasing coefficients in accordance with aspects of the present disclosure; [0013] Figure 5 illustrates another example of a UE transmitting a CSI report that contains a set of co-phasing coefficients in accordance with aspects of the present disclosure; [0014] Figure 6 illustrates an example of a UE apparatus that supports techniques for reporting phase-coupling coefficients with CSI in accordance with aspects of the present disclosure; [0015] Figure 7 illustrates an example of a network equipment (“NE”) apparatus that supports techniques for reporting phase-coupling coefficients with CSI in accordance with aspects of the present disclosure; [0016] Figure 8 illustrates a flowchart diagram of a first method that supports techniques for reporting phase-coupling coefficients with CSI in accordance with aspects of the present disclosure; and [0017] Figure 9 illustrates a flowchart of a second method that supports techniques for reporting phase-coupling coefficients with CSI in accordance with aspects of the present disclosure. DETAILED DESCRIPTION [0018] Disclosed herein are systems, methods, and apparatuses for reporting inter-TRP co- phasing coefficients (also referred to as “phase-coupling” coefficients) for CJT. Here, the co- phasing coefficients are reported in CSI feedback. In certain embodiments, the methods may be performed using computer code embedded on a computer-readable medium. In certain embodiments, an apparatus or system may include a computer-readable medium containing computer-readable code which, when executed by a processor, causes the apparatus or system to perform at least a portion of the below described solutions. [0019] For CSI reporting in 3GPP NR Release 16 specification (“Rel-16”), two types of codebooks are defined. The NR Type-I codebook uses multiple predefined matrices from which a selection is made by UE report and/or Radio Resource Control (“RRC”) Configuration. However, the Type-II codebook is not based on a predefined table, but it is based on a specifically designed mathematical formula with a several parameters. The parameters in the formula are determined by RRC Configuration and/or UE report. The NR Type-II codebook is based on a more detailed CSI report and supports Multi-User Multiple-Input, Multiple-Output (“MU- MIMO”) communication. [0020] For 3GPP NR, within a cell, multiple panel nodes (e.g., multiple TRP and/or multiple Remote Radio Head (“RRH”) nodes) may communicate simultaneously with one UE to enhance coverage, throughput, and/or reliability. The panels (or TRPs/RRHs) may not be co- located, i.e., they may be placed in remote locations. Communicating with the same UE via multiple nodes comes at the expense of excessive control signaling between the network side and the UE side, so as to communicate the best transmission configuration, e.g., whether to support multi-point transmission, and if so, which panel would operate simultaneously, in addition to a possibly super-linear increase in the amount of CSI feedback reported from the UE to the network, since a distinct codebook may be needed for each point. [0021] Aspects of the present disclosure are described in the context of a wireless communications system. Aspects of the present disclosure are further illustrated and described with reference to system diagrams, device diagrams, configuration parameter diagrams, and/or flowcharts. [0022] Figure 1 illustrates an example of a wireless communication system 100 supporting techniques for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as a Long-Term Evolution (“LTE”) network or an LTE-Advanced (“LTE-A”) network. In some other implementations, the wireless communications system 100 may be a 5G network, such as an NR network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (“IEEE”) 802.11 (i.e., Wi- Fi), IEEE 802.16 (i.e., WiMAX), IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (“TDMA”), frequency division multiple access (“FDMA”), or code division multiple access (“CDMA”), etc. [0023] In one embodiment, the wireless communication system 100 includes at least one remote unit 105, a RAN 120, and a mobile core network 140. The RAN 120 and the mobile core network 140 form a mobile communication network. The RAN 120 may be composed of at least one base station unit 121 with which the remote unit 105 communicates using wireless communication links 123. Even though a specific number of remote units 105, RANs 120, base station units 121, wireless communication links 123, and mobile core networks 140 are depicted in Figure 1, one of skill in the art will recognize that any number of remote units 105, RANs 120, base station units 121, wireless communication links 123, and mobile core networks 140 may be included in the wireless communication system 100. [0024] In one implementation, the RAN 120 is compliant with the Fifth Generation (“5G”) cellular system specified in the Third Generation Partnership Project (“3GPP”) specifications. For example, the RAN 120 may be a Next Generation Radio Access Network (“NG-RAN”), implementing NR Radio Access Technology (“RAT”) and/or LTE RAT. In another example, the RAN 120 may include non-3GPP RAT (e.g., Wi-Fi® or IEEE 802.11-family compliant wireless local area network (“WLAN”)). In another implementation, the RAN 120 is compliant with the LTE system specified in the 3GPP specifications. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication network, for example, the Worldwide Interoperability for Microwave Access (“WiMAX”) or IEEE 802.16-family standards, among other networks. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol. [0025] In one embodiment, the remote units 105 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (“PDAs”), tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet), smart appliances (e.g., appliances connected to the Internet), set-top boxes, game consoles, security systems (including security cameras), vehicle on-board computers, network devices (e.g., routers, switches, modems), or the like. In some embodiments, the remote units 105 include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the remote units 105 may be referred to as the UEs, subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, user terminals, wireless transmit/receive unit (“WTRU”), a device, or by other terminology used in the art. In various embodiments, the remote unit 105 includes a subscriber identity and/or identification module (“SIM”) and the mobile equipment (“ME”) providing mobile termination functions (e.g., radio transmission, handover, speech encoding and decoding, error detection and correction, signaling and access to the SIM). In certain embodiments, the remote unit 105 may include a terminal equipment (“TE”) and/or be embedded in an appliance or device (e.g., a computing device, as described above). [0026] The remote units 105 may communicate directly with one or more of the base station units 121 in the RAN 120 via uplink (“UL”) and downlink (“DL”) communication signals. Furthermore, the UL and DL communication signals may be carried over the wireless communication links 123. Furthermore, the UL communication signals may comprise one or more UL channels, such as the Physical Uplink Control Channel (“PUCCH”) and/or Physical Uplink Shared Channel (“PUSCH”), while the DL communication signals may comprise one or more DL channels, such as the Physical Downlink Control Channel (“PDCCH”) and/or Physical Downlink Shared Channel (“PDSCH”). Here, the RAN 120 is an intermediate network that provides the remote units 105 with access to the mobile core network 140. [0027] In various embodiments, the remote unit 105 receives a CSI reporting configuration 125 from the base station unit 121. As described in greater detail below, the CSI reporting configuration 125 may configure the remote unit 105 to include a CSI reporting setting that indicates a precoder restriction. Moreover, after receiving a set of channel measurement reference signals (including at least one NZP CSI-RS) from multiple network nodes (e.g., multiple base station units 121, or multiple TRP/RRH nodes associated with the same base station unit 121), the remote unit 105 may generating CSI feedback report 127 comprising a Precoder Matrix Indicator (“PMI”) value derived based on the NZP CSI-RS in accordance with the CSI reporting configuration 125. Additionally, the remote unit 105 transmits the CSI feedback report 127 to the base station unit 121, e.g., over a physical uplink channel. [0028] In various embodiments, the remote units 105 may communicate directly with each other (e.g., device-to-device communication) using sidelink (“SL”) communication 113. Here, SL transmissions may occur on SL resources. A remote unit 105 may be provided with different SL communication resources according to different allocation modes. For example, in 3GPP systems, allocation Mode-1 corresponds to a NR-based network-scheduled SL communication mode, wherein the in-coverage RAN 120 indicates resources for use in SL operation, including resources of one or more resource pools. Allocation Mode-2 corresponds to a NR-based UE-scheduled SL communication mode (i.e., UE-autonomous selection), where the remote unit 105 selects a resource pools and resources therein from a set of candidate pools. Allocation Mode-3 corresponds to an LTE-based network-scheduled SL communication mode. Allocation Mode-4 corresponds to an LTE-based UE-scheduled SL communication mode (i.e., UE-autonomous selection). [0029] As used herein, a “resource pool” refers to a set of resources assigned for SL operation. A resource pool consists of a set of RBs (i.e., Physical Resource Blocks (“PRBs”)) over one or more time units (e.g., subframe, slots, Orthogonal Frequency Division Multiplexing (“OFDM”) symbols). In some embodiments, the set of RBs comprises contiguous PRBs in the frequency domain. A Physical Resource Block (“PRB”), as used herein, consists of twelve consecutive subcarriers in the frequency domain. [0030] In some embodiments, the remote units 105 communicate with an application server 151 via a network connection with the mobile core network 140. For example, an application 107 (e.g., web browser, media client, telephone and/or Voice-over-Internet-Protocol (“VoIP”) application) in a remote unit 105 may trigger the remote unit 105 to establish a protocol data unit (“PDU”) session (or Packet Data Network (“PDN”) connection) with the mobile core network 140 via the RAN 120. The PDU session represents a logical connection between the remote unit 105 and the User Plane Function (“UPF”) 141. The mobile core network 140 then relays traffic between the remote unit 105 and the application server 151 in the packet data network 150 using the PDU session (or other data connection). [0031] In order to establish the PDU session (or PDN connection), the remote unit 105 must be registered with the mobile core network 140 (also referred to as “attached to the mobile core network” in the context of a Fourth Generation (“4G”) system). Note that the remote unit 105 may establish one or more PDU sessions (or other data connections) with the mobile core network 140. As such, the remote unit 105 may have at least one PDU session for communicating with the packet data network 150. The remote unit 105 may establish additional PDU sessions for communicating with other data networks and/or other communication peers. [0032] In the context of a 5G system (“5GS”), the term “PDU Session” refers to a data connection that provides end-to-end (“E2E”) user plane (“UP”) connectivity between the remote unit 105 and a specific Data Network (“DN”) through the UPF 141. A PDU Session supports one or more Quality of Service (“QoS”) Flows. In certain embodiments, there may be a one-to-one mapping between a QoS Flow and a QoS profile, such that all packets belonging to a specific QoS Flow have the same 5G QoS Identifier (“5QI”). [0033] In the context of a 4G/LTE system, such as the Evolved Packet System (“EPS”), a PDN connection (also referred to as EPS session) provides E2E UP connectivity between the remote unit and a PDN. The PDN connectivity procedure establishes an EPS Bearer, i.e., a tunnel between the remote unit 105 and a PDN Gateway (“PGW”) (not shown in Figure 1) in the mobile core network 140. In certain embodiments, there is a one-to-one mapping between an EPS Bearer and a QoS profile, such that all packets belonging to a specific EPS Bearer have the same QoS Class Identifier (“QCI”). [0034] The base station units 121 may be distributed over a geographic region. In certain embodiments, a base station unit 121 may also be referred to as an access terminal, an access point, a base, a base station, a Node-B (“NB”), an Evolved Node B (abbreviated as eNodeB or “eNB,” also known as Evolved Universal Terrestrial Radio Access Network (“E-UTRAN”) Node B), a 5G/NR Node B (“gNB”), a Home Node-B, a relay node, a RAN node, or by any other terminology used in the art. The base station units 121 are generally part of a RAN, such as the RAN 120, that may include one or more controllers communicably coupled to one or more corresponding base station units 121. These and other elements of radio access network are not illustrated but are well known generally by those having ordinary skill in the art. The base station units 121 connect to the mobile core network 140 via the RAN 120. [0035] The base station units 121 may serve a number of remote units 105 within a serving area, for example, a cell or a cell sector, via a wireless communication link 123. The base station units 121 may communicate directly with one or more of the remote units 105 via communication signals. Generally, the base station units 121 transmit DL communication signals to serve the remote units 105 in the time domain, frequency domain, and/or spatial domain. Furthermore, the DL communication signals may be carried over the wireless communication links 123. The wireless communication links 123 may be any suitable carrier in licensed or unlicensed radio spectrum. The wireless communication links 123 facilitate communication between one or more of the remote units 105 and/or one or more of the base station units 121. [0036] Note that during NR operation on unlicensed spectrum (referred to as “NR-U”), the base station unit 121 and the remote unit 105 communicate over unlicensed (i.e., shared) radio spectrum. Similarly, during LTE operation on unlicensed spectrum (referred to as “LTE-U”), the base station unit 121 and the remote unit 105 also communicate over unlicensed (i.e., shared) radio spectrum. [0037] In one embodiment, the mobile core network 140 is a 5G Core network (“5GC”) or an Evolved Packet Core (“EPC”), which may be coupled to a packet data network 150, like the Internet and private data networks, among other data networks. A remote unit 105 may have a subscription or other account with the mobile core network 140. In various embodiments, each mobile core network 140 belongs to a single mobile network operator (“MNO”) and/or Public Land Mobile Network (“PLMN”). The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol. [0038] The mobile core network 140 includes several network functions (“NFs”). As depicted, the mobile core network 140 includes at least one UPF 141. The mobile core network 140 also includes multiple control plane (“CP”) functions including, but not limited to, an Access and Mobility Management Function (“AMF”) 143 that serves the RAN 120, a Session Management Function (“SMF”) 145, a Policy Control Function (“PCF”) 147, a Unified Data Management function (“UDM”) and a User Data Repository (“UDR”). In some embodiments, the UDM is co-located with the UDR, depicted as combined entity “UDM/UDR” 149. Although specific numbers and types of network functions are depicted in Figure 1, one of skill in the art will recognize that any number and type of network functions may be included in the mobile core network 140. [0039] The UPF(s) 141 is/are responsible for packet routing and forwarding, packet inspection, QoS handling, and external PDU session for interconnecting Data Network (“DN”), in the 5G architecture. The AMF 143 is responsible for termination of Non-Access Spectrum (“NAS”) signaling, NAS ciphering and integrity protection, registration management, connection management, mobility management, access authentication and authorization, security context management. The SMF 145 is responsible for session management (i.e., session establishment, modification, release), remote unit (i.e., UE) Internet Protocol (“IP”) address allocation and management, DL data notification, and traffic steering configuration of the UPF 141 for proper traffic routing. [0040] The PCF 147 is responsible for unified policy framework, providing policy rules to CP functions, access subscription information for policy decisions in UDR. The UDM is responsible for generation of Authentication and Key Agreement (“AKA”) credentials, user identification handling, access authorization, subscription management. The UDR is a repository of subscriber information and may be used to service a number of network functions. For example, the UDR may store subscription data, policy-related data, subscriber-related data that is permitted to be exposed to third party applications, and the like. [0041] In various embodiments, the mobile core network 140 may also include a Network Repository Function (“NRF”) (which provides Network Function (“NF”) service registration and discovery, enabling NFs to identify appropriate services in one another and communicate with each other over Application Programming Interfaces (“APIs”)), a Network Exposure Function (“NEF”) (which is responsible for making network data and resources easily accessible to customers and network partners), an Authentication Server Function (“AUSF”), or other NFs defined for the 5GC. When present, the AUSF may act as an authentication server and/or authentication proxy, thereby allowing the AMF 143 to authenticate a remote unit 105. In certain embodiments, the mobile core network 140 may include an authentication, authorization, and accounting (“AAA”) server. [0042] In various embodiments, the mobile core network 140 supports different types of mobile data connections and different types of network slices, wherein each mobile data connection utilizes a specific network slice. Here, a “network slice” refers to a portion of the mobile core network 140 optimized for a certain traffic type or communication service. For example, one or more network slices may be optimized for enhanced mobile broadband (“eMBB”) service. As another example, one or more network slices may be optimized for ultra-reliable low- latency communication (“URLLC”) service. In other examples, a network slice may be optimized for machine-type communication (“MTC”) service, massive MTC (“mMTC”) service, Internet- of-Things (“IoT”) service. In yet other examples, a network slice may be deployed for a specific application service, a vertical service, a specific use case, etc. [0043] A network slice instance may be identified by a single-network slice selection assistance information (“S-NSSAI”) while a set of network slices for which the remote unit 105 is authorized to use is identified by network slice selection assistance information (“NSSAI”). Here, “NSSAI” refers to a vector value including one or more S-NSSAI values. In certain embodiments, the various network slices may include separate instances of network functions, such as the SMF 145 and UPF 141. In some embodiments, the different network slices may share some common network functions, such as the AMF 143. The different network slices are not shown in Figure 1 for ease of illustration, but their support is assumed. [0044] While Figure 1 illustrates exemplary components of a 5G RAN and a 5G core network, the described embodiments for precoder restrictions for CSI feedback apply to other types of communication networks and RATs, including IEEE 802.11 variants, Global System for Mobile Communications (“GSM”) (i.e., a 2G digital cellular network), General Packet Radio Service (“GPRS”), Universal Mobile Telecommunications System (“UMTS”), LTE variants, CDMA2000, Bluetooth, ZigBee, Sigfox, and the like. [0045] Moreover, in an LTE variant where the mobile core network 140 is an EPC, the depicted network functions may be replaced with appropriate EPC entities, such as a Mobility Management Entity (“MME”), a Serving Gateway (“SGW”), a PGW, a Home Subscriber Server (“HSS”), and the like. For example, the AMF 143 may be mapped to an MME, the SMF 145 may be mapped to a control plane portion of a PGW and/or to an MME, the UPF 141 may be mapped to an SGW and a user plane portion of the PGW, the UDM/UDR 149 may be mapped to an HSS, etc. [0046] In the following descriptions, the term “RAN node” is used for the base station unit, but it is replaceable by any other radio access node, e.g., gNB, ng-eNB, eNB, Base Station (“BS”), base unit, next-generation eNB (“ng-eNB”), Access Point (“AP”), etc. Additionally, the term “UE” is used for the mobile station/ remote unit, but it is replaceable by any other remote device, e.g., remote unit, WTRU, MS, ME, etc. Further, the operations are described mainly in the context of 5G NR; however, the proposed solutions/methods are also equally applicable to other mobile communication systems supporting reporting phase-coupling coefficients with CSI. [0047] Figure 2 illustrates an example of a NR protocol stack 200, in accordance with aspects of the present disclosure. While Figure 2 shows the UE 205, the RAN node 210 and a 5G core network (“5GC”) 215, these are representative of a set of remote units 105 interacting with a base station unit 121 and a mobile core network 140. As depicted, the NR protocol stack 200 comprises a User Plane protocol stack 201 and a Control Plane protocol stack 203. The User Plane protocol stack 201 includes a physical (“PHY”) layer 220, a Medium Access Control (“MAC”) sublayer 225, the Radio Link Control (“RLC”) sublayer 230, a Packet Data Convergence Protocol (“PDCP”) sublayer 235, and Service Data Adaptation Protocol (“SDAP”) layer 240. The Control Plane protocol stack 203 includes a PHY layer 220, a MAC sublayer 225, a RLC sublayer 230, and a PDCP sublayer 235. The Control Plane protocol stack 203 also includes a Radio Resource Control (“RRC”) layer 245 and a Non-Access Stratum (“NAS”) layer 250. [0048] The AS layer 255 (also referred to as “AS protocol stack”) for the User Plane protocol stack 201 consists of at least SDAP, PDCP, RLC and MAC sublayers, and the physical layer. The AS layer 260 for the Control Plane protocol stack 203 consists of at least RRC, PDCP, RLC and MAC sublayers, and the physical layer. The Layer-1 (“L1”) includes the PHY layer. The Layer-2 (“L2”) is split into the SDAP, PDCP, RLC and MAC sublayers. The Layer-3 (“L3”) includes the RRC layer 245 and the NAS layer 250 for the control plane and includes, e.g., an IP layer and/or PDU Layer (not depicted) for the user plane. L1 and L2 are referred to as “lower layers,” while L3 and above (e.g., transport layer, application layer) are referred to as “higher layers” or “upper layers.” [0049] The PHY layer 220 offers transport channels to the MAC sublayer 225. The PHY layer 220 may perform a beam failure detection procedure using energy detection thresholds, as described herein. In certain embodiments, the PHY layer 220 may send an indication of beam failure to a MAC entity at the MAC sublayer 225. The MAC sublayer 225 offers logical channels to the RLC sublayer 230. The RLC sublayer 230 offers RLC channels to the PDCP sublayer 235. The PDCP sublayer 235 offers radio bearers to the SDAP sublayer 240 and/or RRC layer 245. The SDAP sublayer 240 offers QoS flows to the core network (e.g., 5GC). The RRC layer 245 provides for the addition, modification, and release of Carrier Aggregation and/or Dual Connectivity. The RRC layer 245 also manages the establishment, configuration, maintenance, and release of Signaling Radio Bearers (“SRBs”) and Data Radio Bearers (“DRBs”). [0050] The NAS layer 250 is between the UE 205 and an AMF in the 5GC 215. NAS messages are passed transparently through the RAN. The NAS layer 250 is used to manage the establishment of communication sessions and for maintaining continuous communications with the UE 205 as it moves between different cells of the RAN. In contrast, the AS layers 255 and 260 are between the UE 205 and the RAN (i.e., RAN node 210) and carry information over the wireless portion of the network. While not depicted in Figure 2, the IP layer exists above the NAS layer 250, a transport layer exists above the IP layer, and an application layer exists above the transport layer. [0051] The MAC sublayer 225 is the lowest sublayer in the L2 architecture of the NR protocol stack. Its connection to the PHY layer 220 below is through transport channels, and the connection to the RLC sublayer 230 above is through logical channels. The MAC sublayer 225 therefore performs multiplexing and demultiplexing between logical channels and transport channels: the MAC sublayer 225 in the transmitting side constructs MAC PDUs (also known as Transport Blocks (“TBs”)) from MAC Service Data Units (“SDUs”) received through logical channels, and the MAC sublayer 225 in the receiving side recovers MAC SDUs from MAC PDUs received through transport channels. [0052] The MAC sublayer 225 provides a data transfer service for the RLC sublayer 230 through logical channels, which are either control logical channels which carry control data (e.g., RRC signaling) or traffic logical channels which carry user plane data. On the other hand, the data from the MAC sublayer 225 is exchanged with the PHY layer 220 through transport channels, which are classified as UL or DL. Data is multiplexed into transport channels depending on how it is transmitted over the air. [0053] The PHY layer 220 is responsible for the actual transmission of data and control information via the air interface, i.e., the PHY layer 220 carries all information from the MAC transport channels over the air interface on the transmission side. Some of the important functions performed by the PHY layer 220 include coding and modulation, link adaptation (e.g., Adaptive Modulation and Coding (“AMC”)), power control, cell search and random access (for initial synchronization and handover purposes) and other measurements (inside the 3GPP system (i.e., NR and/or LTE system) and between systems) for the RRC layer 245. The PHY layer 220 performs transmissions based on transmission parameters, such as the modulation scheme, the coding rate (i.e., the modulation and coding scheme (“MCS”)), the number of Physical Resource Blocks (“PRBs”), etc. [0054] Note that an LTE protocol stack comprises similar structure to the NR protocol stack 200, with the differences that the LTE protocol stack lacks the SDAP sublayer 240 in the AS layer 255 and that the NAS layer 250 is between the UE 205 and an MME in the EPC. [0055] For the 3GPP NR Rel-16 Type-II codebook with high resolution, the number of Precoding Matrix Indicator (“PMI”) bits fed back from the UE 205 to the RAN node 210 (e.g., gNB) via Uplink Control Information (“UCI”) can be very large (>1000 bits at large bandwidth), even for a single-point transmission. The purpose of multi-panel transmission is to improve the spectral efficiency, as well as the reliability and robustness of the connection in different scenarios, and it covers both ideal and nonideal backhaul. For increasing the reliability using multi-panel transmission, URLLC under multi-panel transmission was agreed, where the UE 205 can be served by multiple TRPs forming a coordination cluster, possibly connected to a central processing unit. [0056] In some embodiments, the presence of K panels may trigger up to 2K-1 possible transmission hypotheses. For instance, at K=4, the following 15 transmission hypotheses may be possible: 4 single-TRP transmission hypotheses for TRPs 1, 2, 3, 4; 6 double-TRP transmission hypotheses for TRP pairs {1,2}, {1,3}, {1,4}, {2,3}, {2,4}, {3,4}; 4 triple-TRP transmission hypotheses for TRP triplets {1,2,3}, {1,2,4}, {1,3,4}, {2,3,4}; and 1 quadruple TRP hypothesis for TRP quadruplet {1,2,3,4}. [0057] Disclosed herein are solutions for efficient reporting inter-TRP co-phasing coefficients for CJT. More specifically, for the purpose of supporting CJT in NR, the following solutions are discussed: [0058] According to a first solution, rather than reporting co-phasing coefficients per TRP, two solutions are proposed: reporting co-phasing coefficients per TRP per hypothesis, or alternatively report K versions of co-phasing coefficients for CJT with K TRPs, wherein in each version a distinct TRP is assumed as the reference for co-phasing in each version. [0059] According to a second solution, the UE 205 reports the total number of non-zero coefficients across all PMI in a first part of the two CSI report parts (hereafter “CSI report Part 1”), whereas the total number of non-zero coefficients per PMI is reported in a second part of the two CSI report parts (hereafter “CSI report Part 2”). Alternatively, only K-1 of the K indicators of the number of non-zero coefficients need to be reported. [0060] In some embodiments, a multi-panel codebook may be provided and used to report CSI feedback for CJT. For example, the UE 205 may be configured to reuse the 3GPP Release 15 specification (“Rel-15”) Type-I multi-panel codebook for multi-TRP with co-phasing introduced between two panels. However, Rel-15 Type-I multi-panel codebook co-phasing is designed for the case of two panels, with all panels activate simultaneously; therefore, this codebook may be unsuitable to support CJT in NR because under CJT framework more than two panels/TRPs may be selected, with a subset of the panels/TRPs may be selected/omitted. [0061] In some embodiments, the UE 205 may report the total number of non-zero coefficients across all precoding matrices reported in a CSI report. However, while this parameter would successfully characterize the CSI report size, it would not enable identifying the feedback bits corresponding to a particular PMI. Alternatively, if the number of nom-zero coefficients are reported separately for each precoding matrix, the overhead of the CSI report Part 1 increases significantly, which is undesirable since the CSI report Part 1 is encoded with a lower rate compared with the CSI report Part 2. [0062] Regarding the 3GPP NR Rel-15 Type-II Codebook, it is assumed that the gNB is equipped with a two-dimensional (“2D”) antenna array with N1, N2 antenna ports per polarization placed horizontally and vertically and communication occurs over N3 PMI sub-bands. A PMI subband consists of a set of resource blocks, each resource block consisting of a set of subcarriers. In such case, 2N1N2 CSI-RS ports are utilized to enable DL channel estimation with high resolution for NR Rel-15 Type-II codebook. Further details on NR codebook types can be found in 3GPP Technical Specification (“TS”) 38.214. [0063] In order to reduce the UL feedback overhead, a Discrete Fourier Transform (“DFT”)-based CSI compression of the spatial domain (“SD”) is applied to L dimensions per polarization, where L<N1N2. In the following, the indices of the 2L dimensions are referred as the SD basis indices. The magnitude and phase values of the linear combination coefficients for each subband are fed back to the gNB as part of the CSI report. The 2N1N2×N3 codebook per transmission layer takes on the form: ^ = ^ _^ ^ _^ where the matrix W1 is a 2N1N2×2L block-diagonal matrix (L<N1N2) with two identical diagonal blocks, i.e., ^ _^ = ^ ^{^ ^} ^ _^ ^, and the matrix B is an N ₁ N ₂ ×L matrix from a 2D oversampled DFT matrix, as follows: ^ ^{^ = ^} _{1 ^} ^{^} ^^^ ^^^^^ _^ ^^^ ^ ^{^^^} ⋯ ^ ^{^} _^^^^ ^ ^ where the superscript ^T denotes a matrix transposition operation. Note that O1, O2 oversampling factors are assumed for the 2D DFT matrix from which matrix B is drawn. [0064] Note that the matrix W1 is common across all transmission layers. The matrix W2 is a 2L×N3 matrix, where the i ^th column corresponds to the linear combination coefficients of the 2L beams in the i ^th subband. Only the indices of the L selected columns of B are reported, along with the oversampling index taking on O1O2 values. Note that W ₂ are independent for different transmission layers. [0065] Regarding 3GPP NR Rel-15, for Type-II Port Selection (“PS”) codebook, only K (where K ≤ 2N1N2) beamformed CSI-RS ports are utilized in DL transmission, in order to reduce complexity. The K×N ₃ codebook matrix per transmission layer takes on the form: ^ = ^- ^ ^. ^ _^ [0066] Here, the matrices W2 follow the same structure as the conventional NR Rel-15 Type-II Codebook and are transmission layer specific. ^- ^ ^. is a K×2L block-diagonal matrix with two identical diagonal blocks, i.e., ^- ^ ^. = ^ ^{/ ^} ^ _/ ^, 0 and E is a ×L matr ^ ix whose columns vectors, as follows: / = ^^ ^{^0/^^} ^ ^{^0/^^} … ^{^0/^^} ^, where _" parameter which takes on the values {1,2,3,4} under the condition dPS ≤ min(K/2, L), whereas mPS takes on the values 90, … , : ⁰ ^ ₂₃₄ ; − 1= and is reported as part of the UL CSI feedback overhead. The matrix W ₁ is common all transmission layers. [0067] For K=16, L=4 and dPS =1, the 8 possible realizations of E corresponding to mPS = {0,1,…,7} are as follows

_é ^{1 0} 0 0 0 0ù _é ^{0 0} 0 0 0 0ù _é ^{0 0} 0 0 0 0 _é ^{0 0} 0 0 0 _{1 1 0 0 0} ù _{0 0} 0 0ù ê 0 0 1 0ú ê 0 1 0 0ú ê 1 0 0 0ú ê 0 0 0 0ú ê 0 0 0 1ú ê ú ê ú ê ú ê ú ê 0 0 1 0 0 1 0 0 1 0 0 0 , ú , ê ú ê ú 0 0 0 0 0 0 , , ê ú ê 0 1ú ê 0 0 1 0ú ê 0 1 0 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 0 1ú ê 0 0 1 0ú ê 0 0 0 0 ú ê 0 0 0 0 ú ê 0 0 0 0 ú ê 0 0 0 1 ú ë 0 0 _{0 0} ^û ë 0 0 _{0 0} ^û ë 0 0 _{0 0} ^û ë 0 0 _{0 0} ^û é ^{0 0} 0 0 ^{0 0} 0 1 ^{0 0} 1 0 ^{0 1} 0 0 0 ₀ 0 0ù _{é0 0} 0 0ù _{é0 0} 0 1ù _{é0 0} 1 0ù ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 0 1ú ê 0 0 0 0ú ê 0 0 ú ê ú ê ú ê ú ê 0 0ú ê 0 0 0 0 0 0 0 0 0 0 , ú ê ú 1 0 0 0 0 0 , 0 0 , ê ú ê ú ê 0 0ú ê 0 0 0 0ú ê 0 1 0 0ú ê 1 0 0 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 1 0 ú ê 0 1 0 0 ú ê 1 0 0 0 ú ê 0 0 0 0 ú ë 0 0 _{0 1} ^û ë 0 0 _{1 0} ^û ë 0 1 _{0 0} ^û ë 1 0 _{0 0} ^û [0068] When d _PS =2, the 4 possible realizations of E corresponding to m _PS = {0,1,2,3} are as follows é ^{1 0} 0 0 ^{0 0} 0 0 ^{0 0} 0 0 1 0 0 0ù _é 0 0 _{é 0} 0 0 _é ^{0 0} 0 _{1 0 0} ù ₀ ù _{0 0} 0 1ù ê 0 0 1 0ú ê 1 0 0 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 0 ú ê ú ê ú ê ú ê 1ú 0 1 0 0 0 0 0 0 0 0 0 0 , ê ú ê ú ê ú 0 0 0 0 0 , , . ê ú ê 0 1 0ú ê 1 0 0 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 0 1ú ê 0 1 0 0ú ê 0 0 0 0ú ê 0 0 0 0 ú ê 0 0 0 0 ú ê 0 0 1 0 ú ê 1 0 0 0 ú ë0 0 _{0 0} ^û ë 0 0 _{0 0} ^û ë 0 0 _{0 1} ^û ë 0 1 _{0 0} ^û [0069] When dPS =3, the 3 possible realizations of E corresponding of mPS = {0,1,2} are as follows é ^{1 0} 0 0 ^{0 0} 0 0 ⁰ 1 0 0 ₁ 0 0ù _{é0 0} 0 0ù _é ⁰ 0 ₀ 0 1ù ê 0 0 1 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 0 ú ê ú ê ú ê 1ú ê 1 0 0 0ú ê 0 0 0 0ú 0 0 0 0 , ú ê 0 , ê 1 0 0ú ê 0 0 0 0ú ê 0 0 0 0ú ê 0 0 1 0ú ê 0 0 0 0ú ê 0 0 0 0 ú ê 0 0 0 1 ú ê 1 0 0 0 ú ë 0 0 _{0 0} ^û ë 0 0 _{0 0} ^û ë 0 1 _{0 0} ^û [0070] When dPS =4, the 2 possible realizations of E corresponding of mPS = {0,1} are as follows _é ^{1 0} 0 0 0 0 _é ^{0 0} 0 0 0 ₁ ù _{0 0} 0 0ù ê 0 0 1 0ú ê 0 0 0 0ú ê 0 0 0 1ú ê 0 0 ú ê ú 0 0 , ê ú 0 0 0 0 1 0 0 . ê ú ê 0ú ê 0 0 0 0ú ê 0 1 0 0ú ê 0 0 0 0 ú ê 0 0 1 0 ú ë 0 0 _{0 0} ^û ë 0 0 _{0 1} ^û [0071] To summarize, m _PS parametrizes the location of the first 1 in the first column of E, whereas dPS represents the row shift corresponding to different values of mPS. [0072] Regarding 3GPP NR Rel-15, the Type-I codebook is the baseline codebook for NR, with a variety of configurations. The most common utility of Rel-15 Type-I codebook is a special case of NR Rel-15 Type-II codebook with L=1 for Rank Indicator (“RI”)=1,2, wherein a phase coupling value is reported for each subband, i.e., W _2,l is 2×N3, with the first row equal to [1, 1, …, 1] and the second row equal to E^ ^{^^^∅^} , … , ^ ^{^^^∅GH^^} I. Under specific configurations, ϕ ₀ = ϕ ₁ …= ϕ, i.e., wideband reporting. For RI>2, different beams are used for each pair of layers. The NR Rel-15 Type-I codebook may be depicted as a low-resolution version of NR Rel-15 Type- II codebook with spatial beam selection per transmission-layer-pair and phase combining only. [0073] Regarding the 3GPP NR Rel-16 Type-II Codebook, it is assumed that the gNB is equipped with a 2D antenna array with N1, N2 antenna ports per polarization placed horizontally and vertically and communication occurs over N3 PMI subbands. A PMI subband consists of a set of resource blocks, each resource block consisting of a set of subcarriers. In such case, 2N1N2N3 CSI-RS ports are utilized to enable DL channel estimation with high resolution for NR Rel-16 Type-II codebook. In order to reduce the UL feedback overhead, a DFT-based CSI compression of the SD is applied to L dimensions per polarization, where L<N1N2. Similarly, additional compression in the Frequency Domain (“FD”) is applied, where each beam of the FD precoding vectors is transformed using an inverse DFT matrix to the delay domain, and the magnitude and phase values of a subset of the delay-domain coefficients are selected and fed back to the gNB as part of the CSI report. [0074] The 2N ₁ N ₂ ×N ₃ codebook per transmission layer takes on the form: ^ = ^ _^ ^J ^ _^,^ ^ _K ^L where the matrix W1 is a 2N1N2×2L block-diagonal matrix (L<N1N2) with two identical diagonal blocks, i.e., ^ _^ ^{^^ ^} and the matrix B is an N1N2×L matrix with columns drawn from a 2D oversampled DFT matrix, as follows: ^^^^ ^ ^ ^^^ ^ ^^ ^ ^{= ^} _{1 ^} ^{^ ^^^^} ⋯ ^ ^{^} _{^ ^^^^ ^} , ^ , where the ^H denotes a matrix Hermitian, i.e., conjugate transposition operator. Note that O1, O2 oversampling factors are assumed for the 2D DFT matrix from which matrix B is drawn. Note that W ₁ is common across all transmission layers. In various embodiments, the above parameters comply with 3GPP TS 38.214 definitions and procedures. [0075] The matrices W _f,l are an N ₃ ×M matrices (where M < N ₃ ) with columns selected from a critically-sampled size-N3 DFT matrix, as follows: ^ _K,^ = ^{^M} _N^ ^M _N^ ^{⋯ M} _NOP^^ , 0 ≤ Q _" ≤ + _R − 1 ^^N ^^ ^ MN ^{= ^} _{1 ^} ^{^^ ^H} ⋯ ^ ^{^^} N^^ _H ^^^ ^ _H ^ [0076] Only the are reported, along with the oversampling index taking on O1O2 values. Similarly, for Wf,l, only the indices of the M selected columns out of the predefined size-N ₃ DFT matrix are reported. In the sequel the indices of the M dimensions are referred as the selected FD basis indices. Hence, L, M represent the equivalent spatial and frequency dimensions after compression, respectively. Finally, the 2L×M matrix ^ ^J _^ represents the linear combination coefficients (“LCCs”) of the spatial and frequency DFT-basis vectors. Both ^ ^J _^,^ , ^ _M,S are selected independently for different transmission layers. [0077] Amplitude (i.e., magnitude) and phase values of an approximately β fraction of the 2LM available coefficients are reported to the gNB (β<1) as part of the CSI report. Note that coefficients with zero magnitude are indicated via a per-layer bitmap. Since all coefficients reported within a transmission layer are normalized with respect to the coefficient with the largest magnitude (strongest coefficient), the relative value of that coefficient is set to unity (i.e., one), and no magnitude or phase information is explicitly reported for this coefficient. Only an indication of the index of the strongest coefficient per transmission layer is reported. Hence, amplitude and phase values of a maximum of ⌈2βLM⌉-1 coefficients (along with the indices of selected L, M DFT vectors) are reported per transmission layer, leading to significant reduction in CSI report size, compared with reporting 2N1N2×N3-1 coefficients’ information of a theoretical design. [0078] Regarding 3GPP NR II PS codebook, only K beamformed CSI- RS ports are utilized in DL transmission (where K ≤ 2N1N2), in order to reduce complexity. The K×N ³ codebook matrix per transmission layer takes on the form: ^ = ^- ^ ^. ^ ^J _^ ^ _K ^L where the superscript ^H denotes a matrix Hermitian, i.e., conjugate transposition operator. [0079] Here, ^ ^J _^ and Wf follow the same structure as the conventional NR Rel-16 Type-II Codebook, described above, where both are transmission layer specific. The matrix ^- ^ ^. is a K×2L block-diagonal matrix with the same structure as that in the NR Rel-15 Type-II PS Codebook, described above. [0080] Regarding codebook reporting, the CSI codebook report may be partitioned into two parts based on the priority of information reported. Each part is encoded separately. Note that Part 1 of the codebook report (i.e., CSI report Part 1) may possibly have a higher code rate. Below is listed list the parameters for NR Rel-16 Type-II codebook only. More details can be found in TS 38.214, Sections 5.2.3 and 5.2.4. [0081] Regarding the contents of the CSI report, the CSI report Part 1 comprises a RI, plus a Channel Quality Indicator (“CQI”), plus the total number of coefficients (i.e., represented using a single value). The CSI report Part 2 comprises a SD basis indicator, plus a FD basis indicator per layer, plus a bitmap per layer, plus coefficient amplitude information per layer, plus coefficient phase information per layer, plus a strongest coefficient indicator per layer. [0082] Furthermore, the CSI report Part 2 can be decomposed into sub-parts each with different priority (higher priority information listed first). Such partitioning is required to allow dynamic reporting size for codebook based on available resources in the uplink phase. More details can be found in 3GPP TS 38.214, Section 5.2.3. [0083] Also Type-II codebook is based on aperiodic CSI reporting, and only reported in PUSCH via Downlink Control Information (“DCI”) triggering (one exception). Type-I codebook can be based on periodic CSI reporting (e.g., PUCCH) or semi-persistent CSI reporting (e.g., PUSCH or PUCCH) or aperiodic reporting (e.g., PUSCH). [0084] Regarding priority reporting for the CSI report Part 2, note that multiple (i.e., up to N _Rep ) CSI reports may be transmitted, whose priority are shown in Table 1, below: Priority 0: ' ' ' 2 2 2 2 Priority 2+ _VWX − 1: Priority 2+ _VWX : ' ' ' ' [0085] Note that the priority of the N _Rep CSI reports are based on the following: A CSI report corresponding to one CSI reporting configuration for one cell may have higher priority compared with another CSI report corresponding to one other CSI reporting configuration for the same cell; CSI reports intended to one cell may have higher priority compared with other CSI reports intended to another cell; CSI reports may have higher priority based on the CSI report content, e.g., CSI reports carrying L1-RSRP information have higher priority; and CSI reports may have higher priority based on their type, e.g., whether the CSI report is aperiodic, semi-persistent or periodic, and whether the report is sent via PUSCH or PUCCH, may impact the priority of the CSI report. [0086] In light of that, CSI reports may be prioritized as follows, where CSI reports with lower IDs have higher priority Pri _{"]^_} ^`, Q, a, b^ = 2 ∙ + <sub>dW^^e</sub> ∙ f <sub>e</sub> ∙ ` + + _dW^^e ∙ f _e ∙ Q + f _e ∙ a + b where s represents the CSI reporting configuration index; Ms represents the maximum number of CSI reporting configurations; c represents Cell index, Ncells represents the number of serving cells; k has a value of 0 for CSI reports carrying L1-RSRP or L1-SINR, and a value of 1 otherwise; and y has a value of 0 for aperiodic reports, a value of 1 for semi-persistent reports on PUSCH, a value of 2 for semi-persistent reports on PUCCH, and a value of 3 for periodic reports. [0087] Regarding UCI Bit Sequence Generation, the bitwidth for RI, Layer Indicator (“LI”), Wideband (“WB”) CQI for the first TB, WB CQI for the second TB, Subband differential (“ΔSB”) CQI for the first TB, ΔSB CQI for the second TB and CSI-RS Resource Indicator (“CRI”) of codebookType = typeI-SinglePanel is provided in Table 2, below: Bitwidth ⌉ ^{^} WB CQI v [0088] In Table 2, n _RI , v, and s _e ^{tum^lu} are the number of allowed rank indicator values, the value of the rank and the number of CSI-RS resources in the corresponding resource set, respectively, according to Clause 5.2.2.2.1 of 3GPP TS 38.214. The values of the rank indicator field are mapped to allowed rank indicator values with increasing order, where '0' is mapped to the smallest allowed rank indicator value. [0089] Additional information regarding the CSI report number is described below in Tables 3-8. CSI report CSI fields PMI wideband information fields X ₁ , from left to right as in Tables 6.3.1.1.2-1/2 in 3GPP TS 38.214, if reported I CSI report CSI fields number d d f f a e : appng or er o report art e s o a report, wt su - an or sub-band CQI CSI report CSI fields number I or sub-band CQI Subband differential CQI for the second TB of all even subbands with n n r, a e : appng or er o su - an report art e s o a report wt su - an MI or sub-band CQI [0090] Note that sub-bands for given CSI report n indicated by the higher layer parameter csi-ReportingBand are numbered continuously in the increasing order with the lowest subband of csi-ReportingBand as subband 0. CSI report CSI fields number , se 4 f PortSelection-r16’ codebook [0091] The CSI report content in UCI, whether on PUCCH or PUSCH, is provided in detail in 3GPP TS 38.212. The Rank Indicator (“RI”), if reported, has bitwidth of min^rlog _^ + _X1^^e v, ^⌈ log _^ $ _{V_} ^⌉ ^, where Nports, nRI represent the number of antenna ports and the number of allowed rank indicator values, respectively. On the other hand, the CRI and the Synchronization Signal Block Resource Indicator (“SSBRI”) each have bitwidths of ⌈log _^ s _e ^{]^_^V^} ⌉, ⌈log _^ s _e^ ^{^^} ⌉, respectively, where s _e ^{]^_^V^} is the number of CSI-RS resources in set, and s _e^ ^{^^} is the configured number of Synchronization Signal/Physical Broadcast Channel (“SS/PBCH”) blocks in the corresponding resource set for reporting 'ssb-Index-RSRP'. The mapping order of CSI fields of one CSI report with wideband PMI and wideband CQI on PUCCH is depicted in Table 6, is as follows: CSI report number CSI fields H [0092] Figure 3 illustrates an exemplary scenario 400 of CJT a UE 205 served by multiple TRPs in a coordination cluster connected to a central unit 301, in accordance with aspects of the present disclosure. In the depicted example, the central unit 301 is controls a first TRP 303 (denoted (“TRP-1”), a second TRP 305 (denoted (“TRP-2”), a third TRP 307 (denoted (“TRP-3”), and a fourth TRP 309 (denoted (“TRP-4”). The multiple TRPs 303-309 within a cell may user coherent joint transmissions 311 to communicate simultaneously with the UE 205 to enhance coverage, throughput, and reliability. The different TRPs 303-309 may be allocated different CSI- RS resources, e.g., each TRP 303-309 associated with a distinct CSI-RS partition (also referred to herein as a “CSI-RS unit”), as described in greater detail below. The UE 205 generates (and transmits) a CSI report based on a set of NZP CSI-RS received from one or more of the TRPs 303- 309, as described in greater detail below. [0093] As used herein, the following terms are used interchangeably: TRP, panel, set of antennas, set of antenna ports, uniform linear array, cell, node, radio head, communication (e.g., signals/channels) associated with a control resource set (“CORESET”) pool, communication associated with a TCI state from a transmission configuration comprising at least two TCI states. [0094] Note that for the below described solutions, the codebook type used is arbitrary; flexibility for use different codebook types, e.g., Type-II Rel-16 codebook, Type-II Release 17 (“Rel-17”) codebook, etc. Several solutions are described below. According to a possible embodiment, one or more elements or features from one or more of the described solutions may be combined. [0095] Embodiments of the first solution relate to reporting co-phasing coefficients for multiple TRPs. Regarding CSI-RS resource allocation for K TRPs, each of the multiple TRPs associated with joint transmission, e.g., coherent joint transmissions 311, to the UE 205 are associated with a distinct/exclusive group of CSI-RS units for channel measurement, e.g., K CSI- RS units corresponding to K TRPs, as follows: [0096] In a first implementation of CSI-RS resource allocation for K TRPs, each CSI-RS unit corresponds to a distinct group of CSI-RS ports within a same NZP CSI-RS resource. In other words, K CSI-RS port groups per CSI-RS resource, which value may be configured by RRC signaling. In a first example, an NZP CSI-RS resource comprising N CSI-RS ports is decomposed into K groups of N/K exclusive CSI-RS ports, wherein each CSI-RS port group is associated with a distinct TRP. [0097] In a second example, a CSI-RS resource comprising N CSI-RS ports is decomposed into K groups of n ₁ , n ₂ , …, n _K exclusive CSI-RS ports, wherein n ₁ + n ₂ + … + n _K = N. The CSI- RS port grouping is based on one or more of a pre-defined rule, and higher-layer signaling, e.g., based on MAC control element (“CE”) or RRC signaling. In a third example, each CSI-RS port group corresponds to a different/distinct Code Division Multiplexing (“CDM”) group. In other words, there may be a different CDM group per CSI-RS port group. [0098] In a second implementation of CSI-RS resource allocation for K TRPs, the number of CSI-RS port groups is no larger than the number of CDM groups corresponding to the NZP CSI-RS resource. In other words, the number of CSI-RS port groups is less than or equal to the number of CDM groups. [0099] In a third implementation of CSI-RS resource allocation for K TRPs, each CSI-RS unit corresponds to a distinct NZP CSI-RS resource of an NZP CSI-RS resource set, i.e., a total of K NZP CSI-RS resources within a same NZP CSI-RS resource set are associated with the TCI state(s) corresponding to PDSCH transmission. Under this implementation, an NZP CSI-RS resource ID codepoint may correspond to more than one NZP CSI-RS resource. In other words, there are K CSI-RS resources, with a CSI-RS resource ID codepoint corresponding to K CSI-RS resources. [0100] Regarding reporting co-phasing parameters for the K TRPs, a CSI reporting configuration corresponding to joint transmission configures the UE 205 to feed back a CSI report comprising multiple PMI values corresponding to the multiple TRPs involved in joint transmission, wherein multiple transmission hypotheses corresponding to different sets of TRPs involved in joint transmission are considered. [0101] Alternatively, the UE 205 may be associated with a single PMI associated with K sub-PMI values, i.e., the CSI report comprises a single PMI value, wherein the single PMI value constitutes K sub-PMI values. In one example, a sub-PMI value corresponds to a subset of the set of CSI-RS ports associated with the PMI. In the sequel, assuming that the UE 205 is configured with joint transmission from up to K TRPs, the UE 205 would then feed back a CSI report comprising K PMI, where the term PMI and sub-PMI would be used interchangeably. [0102] In a first implementation of reporting co-phasing parameters for the K TRPs, K-1 co-phasing coefficients are reported corresponding to the K TRPs, wherein the co-phasing coefficient values are computed with respect to a reference co-phasing value. In a first example of the first implementation, the reference co-phasing value corresponds to a phase value of zero, and all other co-phasing value are described relative to the reference co-phasing value. [0103] In a second example of the first implementation, the index of the PMI associated with the reference PMI corresponding to a fixed co-phasing value is reported in the CSI report. In a third example of the first implementation, the index of the PMI associated with the reference PMI corresponding to a fixed co-phasing value is higher-layer configured via higher-layer signaling to the UE 205. [0104] In a fourth example of the first implementation, the index of the PMI associated with the reference PMI corresponding to a fixed co-phasing value is set by a rule, e.g., the PMI associated with the lowest/highest CSI-RS unit index. In other words, in this implementation there are K-1 co-phasing parameters for K PMI with respect to a reference co-phasing (e.g., phase = 0) for 1 PMI. [0105] In a second implementation of reporting co-phasing parameters for the K TRPs, K sets of co-phasing coefficients are reported, wherein each set of co-phasing coefficients corresponds to a distinct reference TRP with a fixed reference co-phasing value, such that each set of the K sets of co-phasing values comprises K-1 co-phasing coefficients, i.e., a total of K×(K-1) co-phasing coefficient values are reported. In a first example, a system with K=4 PMI values reported, i.e., PMI1, PMI2, PMI3, PMI4, would include the following values, depicted in Table 9, wherein ci,j corresponds to a co-phasing coefficient corresponding to PMI j in co-phasing set i, wherein co-phasing set i corresponds to the case where PMI j has a fixed co-phasing coefficient value, e.g., zero. Co-phasing Set 1 c _1,2 , c _1,3 , c _1,4 Co-phasing Set 2 c2,1, c2,3, c2,4 ,4 ,3 [0106] In other words, in accordance with the second implementation, there are K sets of co-phasing parameters, each set containing K-1 coefficients, whereby a total of K×(K-1) co- phasing coefficient values are reported. [0107] Figure 4 illustrates an exemplary scenario 400 of CSI feedback 401 in accordance with the second implementation of reporting co-phasing parameters for the K TRPs. In the depicted example, the UE 205 receives CJT 311 comprising NZP CSI-RS from the TRP-1303, the TRP-2 305, the TRP-3 307, and the TRP-4 309. The UE 205 calculates the co-phasing coefficients (i.e., phase-coupling coefficients) for the 4 TRPs in accordance with the second implementation and transmits CSI feedback 401 containing 4 sets of co-phasing coefficients (denoted as co-phasing sets 1-4) in accordance with Table 9. [0108] In a third implementation of reporting co-phasing parameters for the K TRPs, K sets of co-phasing coefficients (or alternatively K-1 sets) are reported, wherein each set of co- phasing coefficients corresponds to a distinct reference TRP with a fixed reference co-phasing coefficient value, such that each co-phasing set i comprises co-phasing coefficient values corresponding to TRP l, where l >i. In a first example, a system with 4 PMI values reported, i.e., PMI1, PMI2, PMI3, PMI4, would include the following values, depicted in Table 10, where ci,l corresponds to co-phasing coefficient corresponding to PMI _l in co-phasing set i, where co-phasing set i corresponds to the case where PMIl has a fixed co-phasing coefficient value. Co-phasing Set 1 c _1,2 , c _1,3 , c _1,4 , a e 0^0^^^ [0109] More generally, for a system with K PMIs, a total of _^ co-phasing coefficient values are reported in accordance with the second implementation. In other words, there are K sets of co-phasing coefficients, each set i containing co-phasing for PMI _l , where i < l. [0110] Figure 5 illustrates an exemplary scenario 500 of CSI feedback 501 in accordance with the third implementation of reporting co-phasing parameters for the K TRPs. In the depicted example, the UE 205 receives CJT 311 comprising NZP CSI-RS from the TRP-1303, the TRP-2 305, the TRP-3307, and the TRP-4309. The UE 205 calculates the co-phasing coefficients (i.e., phase-coupling coefficients) for the 4 TRPs in accordance with the second implementation and transmits CSI feedback 501 containing 3 (or 4) sets of co-phasing coefficients (denoted as co- phasing sets 1-4) in accordance with Table 10. Note that co-phasing set 4 – being null – does not need to be reported to the network. [0111] In a fourth implementation of reporting co-phasing parameters for the K TRPs, a co-phasing coefficient corresponds to a phase value that is drawn from a codebook of phase values, wherein the codebook of phase values is higher-layer configured by the network, fixed, set by a rule, or some combination thereof. A co-phasing coefficient value drawn from a codebook of P values is expected to be indicated via ^⌈ log _^ ^ ^⌉ bits. In one example, the codebook of phase values are drawn from uniformly/evenly-spaced phase values, e.g., {0, π/2, π, 3π/2} for P=4. In other words, this implementation describes a codebook of co-phasing values. [0112] Embodiments of a second solution relate to reporting the number of non-zero coefficients for multiple PMI. For Rel-16 and Rel-17 Type-II codebook-based CSI reporting, the CSI report is decomposed into two parts, where the two CSI report parts are encoded with different code rate. The CSI report Part 1 is supposed to carry fewer parameters compared with the CSI report Part 2, with the CSI report Part 1 having a fixed size and comprising higher priority parameters compared with those in the CSI report Part 2. [0113] Since the payload of the CSI report Part 2 may not be fixed, the CSI report Part 1 must comprise an indication of the CSI report Part 2 payload size. In Rel-16 and Rel-17 Type-II codebooks, the CSI report Part 2 payload size is inferred via the number of non-zero coefficients reported across all layers corresponding to the reported PMI. Since the CSI report corresponding to CJT comprises multiple PMI, enhancement on reporting the number of non-zero coefficients for multiple PMI is needed. [0114] In a first implementation of the second solution, the CSI report Part 1 comprises a parameter that indicates to the total number of non-zero coefficients across all reported PMI in the CSI report. The number of non-zero coefficients (“NNZC”) per PMI can be inferred from the number of entries of value one in a coefficients’ bitmap corresponding to each PMI, wherein the coefficients’ bitmap identifies the indices of the number of non-zero coefficients per PMI. In other words, this implementation describes reporting total NNZC for all PMI, per NNZC inferred from bitmaps. [0115] In a second implementation of the second solution, for a CSI report with N PMI, where N >1, the CSI report Part 1 comprises a parameter corresponding to the total number of non- zero coefficients across all reported PMI in the CSI report, whereas the CSI report Part 2 comprises N additional parameters comprising the total number of non-zero coefficients for each of the N PMI. In other words, this implementation describes reporting the total NNZC for all PMI, per NNZC reported in the CSI report Part 2. [0116] In a first example of the second implementation, the bitwidth (i.e., number of bits allocated for a parameter) of the parameter corresponding to the number of non-zero coefficients per PMI is based on the respective codebook configuration. In other words, the bitwidth of per NNZC derived from the respective codebook configuration. [0117] In a second example of the second implementation, the bitwidth of the parameter corresponding to the number of non-zero coefficients per PMI is no more than ⌈log _^ ^ _^^^ ⌉ , corresponding to the ceiling of the base-2 logarithmic function of the total number of non-zero coefficients reported in the CSI report Part 1, wherein C _NNZ is the total number of non-zero coefficients across all N PMI. In other words, the bitwidth of per-NNZC is derived from the total NNZC. [0118] In a third example of the second implementation, the bitwidth of the parameter corresponding to the number of non-zero coefficients per panel is restricted by a minimum of the codebook configuration-based parameter restriction per PMI, and ^⌈ log _^ ^ _^^^ ^⌉ . In other words, the bitwidth of per-NNZC is derived from minimum of respective codebook configuration and the total NNZC. [0119] In a third implementation of the second solution, for a CSI report with N PMI, where N >1, the CSI report Part 1 comprises a parameter corresponding to the total number of non- zero coefficients across all reported PMI in the CSI report, whereas CSI report Part 2 comprises N-1 additional parameters comprising the number of non-zero coefficients for N-1 PMI of the N PMI in the CSI report. Note that the number of non-zero coefficients corresponding to the Nth PMI can be derived from total number of non-zero coefficients across all N PMI, in addition to the number of non-zero coefficients for the N-1 PMI, e.g., the number of non-zero coefficients corresponding to the Nth PMI is equal to the total number of non-zero coefficients across all N PMI, subtracted by the sum of the number of non-zero coefficients for the N-1 PMI. In other words, this implementation describes reporting total NNZC for all PMI, N-1 NNZC reported in CSI report Part 2 for N-1 PMI, Nth PMI derived by subtraction. [0120] In a first example of the third implementation, the bitwidth (i.e., number of bits allocated for a parameter) of the parameter corresponding to the number of non-zero coefficients per PMI is based on the respective codebook configuration. In other words, the bitwidth of per NNZC derived from respective codebook configuration. [0121] In a second example of the third implementation, the bitwidth of the parameter corresponding to the number of non-zero coefficients per PMI is no more than ⌈log _^ ^ _^^^ ⌉ , corresponding to the ceiling of the base-2 logarithmic function of the total number of non-zero coefficients reported in the CSI report Part 1, wherein CNNZ is the total number of non-zero coefficients across all N PMI. In other words, the bitwidth of per NNZC is derived from the total NNZC. [0122] In a third example of the third implementation, the bitwidth of the parameter corresponding to the number of non-zero coefficients per panel is restricted by a minimum of the codebook configuration-based parameter restriction per PMI, and ⌈log _^ ^ _^^^ ⌉. In other words, the Bitwidth of per NNZC is derived from minimum of the respective codebook configuration and the total NNZC. [0123] In a fourth example of the third implementation, the N-1 PMI correspond to the N- 1 PMI associated with the lowest CSI-RS unit ID. In other words, per NNZC reported for PMI with the lowest N-1 CSI-RS ID. [0124] In a fifth example of the third implementation, the N-1 PMI correspond to the N-1 PMI associated with the highest CSI-RS resource/port ID. In other words, per NNZC reported for PMI with the highest N-1 CSI-RS ID. [0125] In a sixth example of the third implementation, the N-1 PMI correspond to the N-1 PMI associated with the first N-1 CMRs of the N CMRs corresponding to the N CSI-RS units. In other words, per NNZC reported for PMI with the first N-1 CMRs. [0126] In a seventh example of the third implementation, the N-1 PMI correspond to the N-1 PMI associated with the last N-1 CMRs of the N CMRs corresponding to the N CSI-RS units. In other words, per NNZC reported for PMI with the last N-1 CMRs. [0127] In a fourth implementation of the second solution, for a CSI report with N PMI, the CSI report Part 1 comprises N parameters corresponding to the number of non-zero coefficients across each PMI of the N PMI. Under this implementation, parameters corresponding to numbers of non-zero coefficients of a first subset of the N PMIs are reported in a differential form with respect to parameters corresponding to numbers of non-zero coefficients of a second subset of the N PMIs. [0128] In one example of the fourth implementation, an absolute value of the number of non-zero coefficients for a first PMI of the N PMI is reported, whereas the number of non-zero coefficients corresponding to the remainder N-1 PMI are reported in a differential form with respect to the number of non-zero coefficients corresponding to the first PMI. In other words, this implementation describes N per NNZC reported in the CSI report Part 1, comprising 1 NNZC absolute and N-1 total NNZC differential. [0129] In a fifth implementation of the second solution, for a CSI report with N PMI, N+1 parameters corresponding to the number of non-zero coefficients corresponding to the N PMI is reported, wherein a first of the N+1 parameters corresponds to a total/average of the number of non-zero coefficients across all PMI, and may be reported in the CSI report Part 1. The last N parameters of the N+1 parameters correspond to the number of non-zero coefficients over the N PMIs. [0130] In one example of the fifth implementation, the first of the N+1 parameters comprises a total of the number of non-zero coefficients across the N PMI, whereas the remainder N of the N+1 parameters correspond to the number of non-zero coefficients corresponding to the N PMI, which are reported in a differential form with respect to an average of the number of non- zero coefficients over the N PMI, which can be derived from the first of the N+1 parameters. In other words, there are N+1 total NNZC reported in the CSI report Part 1, comprising 1 NNZC absolute, and N total NNZC differential. [0131] Regarding Antenna Panel/Port, Quasi-co-location (“QCL”), Transmission Configuration Indicator (“TCI”) state, and Spatial Relation, in some embodiments, the terms antenna, panel, and antenna panel are used interchangeably. An antenna panel may be a hardware that is used for transmitting and/or receiving radio signals at frequencies lower than 6GHz, e.g., frequency range 1 (“FR1”), or higher than 6GHz, e.g., frequency range 2 (“FR2”) or millimeter wave (mmWave). In some embodiments, an antenna panel may comprise an array of antenna elements, wherein each antenna element is connected to hardware such as a phase shifter that allows a control module to apply spatial parameters for transmission and/or reception of signals. The resulting radiation pattern may be called a beam, which may or may not be unimodal and may allow the device to amplify signals that are transmitted or received from spatial directions. [0132] In some embodiments, an antenna panel may or may not be virtualized as an antenna port in the specifications. An antenna panel may be connected to a baseband processing module through a radio frequency (“RF”) chain for each of transmission (egress) and reception (ingress) directions. A capability of a device in terms of the number of antenna panels, their duplexing capabilities, their beamforming capabilities, and so on, may or may not be transparent to other devices. In some embodiments, capability information may be communicated via signaling or, in some embodiments, capability information may be provided to devices without a need for signaling. In the case that such information is available to other devices, it can be used for signaling or local decision making. [0133] In some embodiments, a device (e.g., UE, node) antenna panel may be a physical or logical antenna array comprising a set of antenna elements or antenna ports that share a common or a significant portion of an RF chain (e.g., in-phase/quadrature (“I/Q”) modulator, analog to digital (“A/D”) converter, local oscillator, phase shift network). The device antenna panel or “device panel” may be a logical entity with physical device antennas mapped to the logical entity. The mapping of physical device antennas to the logical entity may be up to device implementation. Communicating (receiving or transmitting) on at least a subset of antenna elements or antenna ports active for radiating energy (also referred to herein as active elements) of an antenna panel requires biasing or powering on of the RF chain which results in current drain or power consumption in the device associated with the antenna panel (including power amplifier/low noise amplifier (“LNA”) power consumption associated with the antenna elements or antenna ports). The phrase "active for radiating energy," as used herein, is not meant to be limited to a transmit function but also encompasses a receive function. Accordingly, an antenna element that is active for radiating energy may be coupled to a transmitter to transmit radio frequency energy or to a receiver to receive radio frequency energy, either simultaneously or sequentially, or may be coupled to a transceiver in general, for performing its intended functionality. Communicating on the active elements of an antenna panel enables generation of radiation patterns or beams. [0134] In some embodiments, depending on device’s own implementation, a “device panel” can have at least one of the following functionalities as an operational role of Unit of antenna group to control its transmit (“Tx”) beam independently, Unit of antenna group to control its transmission power independently, Unit of antenna group to control its transmission timing independently. The “device panel” may be transparent to gNB. For certain condition(s), gNB or network can assume the mapping between device’s physical antennas to the logical entity “device panel” may not be changed. For example, the condition may include until the next update or report from device or comprise a duration of time over which the gNB assumes there will be no change to the mapping. A device may report its capability with respect to the “device panel” to the gNB or network. The device capability may include at least the number of “device panels.” In one implementation, the device may support UL transmission from one beam within a panel; with multiple panels, more than one beam (one beam per panel) may be used for UL transmission. In another implementation, more than one beam per panel may be supported/used for UL transmission. [0135] In some of the embodiments described, an antenna port is defined such that the channel over which a symbol on the antenna port is conveyed can be inferred from the channel over which another symbol on the same antenna port is conveyed. [0136] Two antenna ports are said to be quasi-co-located (“QCL’d”) if the large-scale properties of the channel over which a symbol on one antenna port is conveyed can be inferred from the channel over which a symbol on the other antenna port is conveyed. The large-scale properties include one or more of delay spread, Doppler spread, Doppler shift, average gain, average delay, and spatial receive (“Rx”) parameters. Two antenna ports may be QCL’d with respect to a subset of the large-scale properties and different subset of large-scale properties may be indicated by a QCL Type parameter. [0137] The QCL Type parameter can indicate which channel properties are the same between the two reference signals (e.g., on the two antenna ports). Thus, the reference signals can be linked to each other with respect to what the UE can assume about their channel statistics or QCL properties. For example, parameter qcl-Type may take one of the following values: [0138] 'QCL-TypeA': {Doppler shift, Doppler spread, average delay, delay spread} [0139] 'QCL-TypeB': {Doppler shift, Doppler spread} [0140] 'QCL-TypeC': {Doppler shift, average delay} [0141] 'QCL-TypeD': {Spatial Rx parameter} [0142] Spatial Rx parameters may include one or more of: angle of arrival (“AoA”), Dominant AoA, average AoA, angular spread, Power Angular Spectrum (“PAS”) of AoA, average angle of departure (“AoD”), PAS of AoD, transmit/receive channel correlation, transmit/receive beamforming, spatial channel correlation etc. [0143] The values QCL-TypeA, QCL-TypeB, and QCL-TypeC may be applicable for all carrier frequencies, but the value QCL-TypeD may be applicable only in higher carrier frequencies (e.g., mmWave, FR2 and beyond), where essentially the UE may not be able to perform omni- directional transmission, i.e., the UE would need to form beams for directional transmission. A QCL-TypeD parameter between two reference signals A and B, the reference signal A is considered to be spatially co-located with reference signal B and the UE may assume that the reference signals A and B can be received with the same spatial filter (e.g., with the same Rx beamforming weights). [0144] An “antenna port” according to an embodiment may be a logical port that may correspond to a beam (resulting from beamforming) or may correspond to a physical antenna on a device. In some embodiments, a physical antenna may map directly to a single antenna port, in which an antenna port corresponds to an actual physical antenna. Alternately, a set or subset of physical antennas, or antenna set or antenna array or antenna sub-array, may be mapped to one or more antenna ports after applying complex weights, a cyclic delay, or both to the signal on each physical antenna. The physical antenna set may have antennas from a single module or panel or from multiple modules or panels. The weights may be fixed as in an antenna virtualization scheme, such as cyclic delay diversity (“CDD”). The procedure used to derive antenna ports from physical antennas may be specific to a device implementation and transparent to other devices. [0145] In some of the embodiments described, a Transmission Configuration Indication (“TCI”) state associated with a target transmission can indicate parameters for configuring a QCL relationship between the target transmission (e.g., target Reference Signal (“RS”) of Demodulation Reference Signal (“DM-RS”) ports of the target transmission during a transmission occasion) and a source reference signal(s) (e.g., Synchronization Signal Block (“SSB”), CSI-RS, and/or Sounding Reference Signal (“SRS”)) with respect to quasi co-location type parameter(s) indicated in the corresponding TCI state. The TCI describes which reference signals are used as a QCL source, and what QCL properties can be derived from each reference signal. A device can receive a configuration of a plurality of transmission configuration indicator states for a serving cell for transmissions on the serving cell. In some of the embodiments described, a TCI state comprises at least one source RS to provide a reference (UE assumption) for determining QCL and/or spatial filter. [0146] In some of the embodiments described, a spatial relation information associated with a target transmission can indicate parameters for configuring a spatial setting between the target transmission and a reference RS (e.g., SSB/CSI-RS/SRS). For example, the device may transmit the target transmission with the same spatial domain filter used for reception the reference RS (e.g., DL RS such as SSB/CSI-RS). In another example, the device may transmit the target transmission with the same spatial domain transmission filter used for the transmission of the reference RS (e.g., UL RS such as SRS). A device can receive a configuration of a plurality of spatial relation information configurations for a serving cell for transmissions on the serving cell. [0147] Figure 6 illustrates an example of a UE apparatus 600 that may be used for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. In various embodiments, the UE apparatus 600 is used to implement one or more of the solutions described above. The UE apparatus 600 may be an example of a communication device, such as the remote unit 105 and/or the UE 205, as described above. Furthermore, the UE apparatus 600 may include a processor 605, a memory 610, an input device 615, an output device 620, and a transceiver 625. [0148] In some embodiments, the input device 615 and the output device 620 are combined into a single device, such as a touchscreen. In certain embodiments, the UE apparatus 600 may not include any input device 615 and/or output device 620. In various embodiments, the UE apparatus 600 may include one or more of: the processor 605, the memory 610, and the transceiver 625, and may not include the input device 615 and/or the output device 620. [0149] As depicted, the transceiver 625 includes at least one transmitter 630 and at least one receiver 635. In some embodiments, the transceiver 625 communicates with one or more cells (or wireless coverage areas) supported by one or more base station units 121. In various embodiments, the transceiver 625 is operable on unlicensed spectrum. Moreover, the transceiver 625 may include multiple UE panels supporting one or more beams. Additionally, the transceiver 625 may support at least one network interface 640 and/or application interface 645. The application interface(s) 645 may support one or more APIs. The network interface(s) 640 may support 3GPP reference points, such as Uu, N1, PC5, etc. Other network interfaces 640 may be supported, as understood by one of ordinary skill in the art. [0150] The processor 605, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 605 may be a microcontroller, a microprocessor, a central processing unit (“CPU”), a graphics processing unit (“GPU”), an auxiliary processing unit, a field programmable gate array (“FPGA”), or similar programmable controller. In some embodiments, the processor 605 executes instructions stored in the memory 610 to perform the methods and routines described herein. The processor 605 is communicatively coupled to the memory 610, the input device 615, the output device 620, and the transceiver 625. [0151] In various embodiments, the processor 605 controls the UE apparatus 600 to implement the above-described UE behaviors. In certain embodiments, the processor 605 may include an application processor (also known as “main processor”) which manages application- domain and operating system (“OS”) functions and a baseband processor (also known as “baseband radio processor”) which manages radio functions. [0152] In various embodiments, via the transceiver 625, the processor 605 receives a CSI reporting setting and receives, from at least one of a plurality of network nodes, a NZP CSI-RS associated with a CMR, where the CMR includes a plurality of CSI-RS partitions. [0153] In some embodiments, each network node of the plurality of network nodes is associated with a distinct CSI-RS partition of the plurality of CSI-RS partitions. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct NZP CSI-RS resource of the same NZP CSI-RS resource set. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct set of NZP CSI-RS ports. In certain embodiments, each distinct set of NZP CSI-RS ports corresponds to a distinct CDM group. [0154] In various embodiments, the processor 605 generates a CSI report based on the CMR, where the CSI report includes A) a plurality of PM values corresponding to the plurality of CSI-RS partitions, B) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and C) an indication of a total number of coefficients of the plurality of PM values. [0155] In some embodiments, the plurality of PM values corresponds to one or more transmission hypotheses, where each transmission hypothesis corresponds to a coherent joint transmission from a set of the plurality of network nodes, and where each transmission hypothesis corresponds to a distinct subset of the set of phase coupling values. In certain embodiments, the one or more transmission hypotheses consists of K transmission hypotheses, where a respective PM value includes K-1 phase coupling coefficients, where K is a positive integer greater than one. [0156] In some embodiments, the plurality of CSI-RS partitions consists of K CSI-RS partitions, where the CSI report includes K subsets of phase coupling coefficients. In certain embodiments, each subset includes K-1 phase coupling coefficient values, where K is a positive integer greater than one having a value based on a number of the plurality of network nodes. In certain embodiments, the processor 605 calculates each subset based on a network node with a fixed phase-coupling value. In one embodiment, the fixed phase-coupling value is set to zero. [0157] In some embodiments, the indication of the total number of coefficients of the plurality of PM values indicates a total amount of non-zero PM coefficients across all PM values included in the CSI report. In such embodiments, a number of phase-coupling coefficients in the one or more sets of phase-coupling coefficients is not included in the indication of the total number of coefficients. [0158] The processor 605 controls the transceiver 625 to transmit the CSI report to at least one network node of the plurality of network nodes. In some embodiments, the CSI report includes at least two CSI report parts, where the first of the two CSI report parts includes an indication of a total number of non-zero coefficients in the CSI report. In certain embodiments, the plurality of PM values consists of K PM values. In one embodiment, a second of the two CSI report parts includes K indicators of a respective per-PM number of coefficients corresponding to each of the K PM values. In another embodiment, a second of the two CSI report parts includes K-1 indicators of a respective per-PM number of coefficients corresponding to a first K-1 PM values of the K PM values. [0159] The memory 610, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 610 includes volatile computer storage media. For example, the memory 610 may include a random-access memory (“RAM”), including dynamic RAM (“DRAM”), synchronous dynamic RAM (“SDRAM”), and/or static RAM (“SRAM”). In some embodiments, the memory 610 includes non-volatile computer storage media. For example, the memory 610 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 610 includes both volatile and non- volatile computer storage media. [0160] In some embodiments, the memory 610 stores data related to reporting phase- coupling coefficients with CSI. For example, the memory 610 may store parameters, configurations, and the like as described above. In certain embodiments, the memory 610 also stores program code and related data, such as an operating system or other controller algorithms operating on the UE apparatus 600. [0161] The input device 615, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 615 may be integrated with the output device 620, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device 615 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 615 includes two or more different devices, such as a keyboard and a touch panel. [0162] The output device 620, in one embodiment, is designed to output visual, audible, and/or haptic signals. In some embodiments, the output device 620 includes an electronically controllable display or display device capable of outputting visual data to a user. For example, the output device 620 may include, but is not limited to, a Liquid Crystal Display (“LCD”), a Light- Emitting Diode (“LED”) display, an Organic LED (“OLED”) display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the output device 620 may include a wearable display separate from, but communicatively coupled to, the rest of the UE apparatus 600, such as a smart watch, smart glasses, a heads-up display, or the like. Further, the output device 620 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like. [0163] In certain embodiments, the output device 620 includes one or more speakers for producing sound. For example, the output device 620 may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device 620 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the output device 620 may be integrated with the input device 615. For example, the input device 615 and output device 620 may form a touchscreen or similar touch-sensitive display. In other embodiments, the output device 620 may be located near the input device 615. [0164] The transceiver 625 communicates with one or more network functions of a mobile communication network via one or more access networks. The transceiver 625 operates under the control of the processor 605 to transmit messages, data, and other signals and also to receive messages, data, and other signals. For example, the processor 605 may selectively activate the transceiver 625 (or portions thereof) at particular times in order to send and receive messages. [0165] The transceiver 625 includes at least one transmitter 630 and at least one receiver 635. One or more transmitters 630 may be used to provide UL communication signals to a base station unit 121, such as the UL transmissions described herein. Similarly, one or more receivers 635 may be used to receive DL communication signals from the base station unit 121, as described herein. Although only one transmitter 630 and one receiver 635 are illustrated, the UE apparatus 600 may have any suitable number of transmitters 630 and receivers 635. Further, the transmitter(s) 630 and the receiver(s) 635 may be any suitable type of transmitters and receivers. In one embodiment, the transceiver 625 includes a first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and a second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum. [0166] In certain embodiments, the first transmitter/receiver pair used to communicate with a mobile communication network over licensed radio spectrum and the second transmitter/receiver pair used to communicate with a mobile communication network over unlicensed radio spectrum may be combined into a single transceiver unit, for example, a single chip performing functions for use with both licensed and unlicensed radio spectrum. In some embodiments, the first transmitter/receiver pair and the second transmitter/receiver pair may share one or more hardware components. For example, certain transceivers 625, transmitters 630, and receivers 635 may be implemented as physically separate components that access a shared hardware resource and/or software resource, such as for example, the network interface 640. [0167] In various embodiments, one or more transmitters 630 and/or one or more receivers 635 may be implemented and/or integrated into a single hardware component, such as a multi- transceiver chip, a system-on-a-chip, an Application-Specific Integrated Circuit (“ASIC”), or other type of hardware component. In certain embodiments, one or more transmitters 630 and/or one or more receivers 635 may be implemented and/or integrated into a multi-chip module. In some embodiments, other components such as the network interface 640 or other hardware components/circuits may be integrated with any number of transmitters 630 and/or receivers 635 into a single chip. In such embodiment, the transmitters 630 and receivers 635 may be logically configured as a transceiver 625 that uses one or more common control signals or as modular transmitters 630 and receivers 635 implemented in the same hardware chip or in a multi-chip module. [0168] Figure 7 illustrates an example of a network apparatus 700 that may be used for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. In one embodiment, the network apparatus 700 may be one implementation of a network endpoint, such as a base station unit 121, the RAN node 210, the TRP-1303, the TRP-2 305, the TRP-3 307, the TRP-4 309, and/or the network apparatus 700, as described above. Furthermore, the network apparatus 700 may include a processor 705, a memory 710, an input device 715, an output device 720, and a transceiver 725. [0169] In some embodiments, the input device 715 and the output device 720 are combined into a single device, such as a touchscreen. In certain embodiments, the network apparatus 700 may not include any input device 715 and/or output device 720. In various embodiments, the network apparatus 700 may include one or more of: the processor 705, the memory 710, and the transceiver 725, and may not include the input device 715 and/or the output device 720. [0170] As depicted, the transceiver 725 includes at least one transmitter 730 and at least one receiver 735. Here, the transceiver 725 communicates with one or more remote units 105. Additionally, the transceiver 725 may support at least one network interface 740 and/or application interface 745. The application interface(s) 745 may support one or more APIs. The network interface(s) 740 may support 3GPP reference points, such as Uu, N1, N2 and N3. Other network interfaces 740 may be supported, as understood by one of ordinary skill in the art. [0171] The processor 705, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 705 may be a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or similar programmable controller. In some embodiments, the processor 705 executes instructions stored in the memory 710 to perform the methods and routines described herein. The processor 705 is communicatively coupled to the memory 710, the input device 715, the output device 720, and the transceiver 725. [0172] In various embodiments, the network apparatus 700 is a RAN node (e.g., gNB) that communicates with one or more UEs and one or more NFs, as described herein. In such embodiments, the processor 705 controls the network apparatus 700 to perform the above- described RAN behaviors. When operating as a RAN node, the processor 705 may include an application processor (also known as “main processor”) which manages application-domain and operating system (“OS”) functions and a baseband processor (also known as “baseband radio processor”) which manages radio functions. [0173] In various embodiments, via the transceiver 725, the processor 705 transmits a CSI reporting setting and transmits a NZP CSI-RS corresponding to a CMR, where the CMR is associated with a plurality of CSI-RS partitions. [0174] In some embodiments, the plurality of CSI-RS partitions is associated with a plurality of network nodes, where each network node of the plurality of network nodes is associated with a distinct CSI-RS partition of the plurality of CSI-RS partitions. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct NZP CSI-RS resource of the same NZP CSI-RS resource set. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct set of NZP CSI-RS ports. In certain embodiments, each distinct set of NZP CSI-RS ports corresponds to a distinct CDM group. [0175] The processor 705 controls the transceiver 725 to receive a CSI report based on the CMR, where the CSI report includes: i) a plurality of PM values corresponding to the plurality of CSI-RS partitions, ii) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and iii) an indication of a total number of coefficients of the plurality of PM values. [0176] In some embodiments, the plurality of CSI-RS partitions is associated with a plurality of network nodes and the plurality of PM values corresponds to one or more transmission hypotheses. In such embodiments, each transmission hypothesis corresponds to a coherent joint transmission from a set of the plurality of network nodes, where each transmission hypothesis corresponds to a distinct subset of the set of phase coupling values. In certain embodiments, the one or more transmission hypotheses consists of K transmission hypotheses, where a respective PM value includes K-1 phase coupling coefficients, where K is a positive integer greater than one. [0177] In some embodiments, the plurality of CSI-RS partitions is associated with the plurality of network nodes, where the plurality of CSI-RS partitions consists of K CSI-RS partitions, and where the CSI report includes K subsets of phase coupling coefficients. In certain embodiments, each subset includes K-1 phase coupling coefficient values, where K is a positive integer greater than one having a value based on a number of a plurality of network nodes. In certain embodiments, the instructions are executable by the processor to cause the first apparatus to calculate each subset based on a network node with a fixed phase-coupling value. In one embodiment, the fixed phase-coupling value is set to zero. [0178] In some embodiments, the indication of the total number of coefficients of the plurality of PM values indicates a total amount of non-zero PM coefficients across all PM values included in the CSI report. In such embodiments, a number of phase-coupling coefficients in the one or more sets of phase-coupling coefficients is not included in the indication of the total number of coefficients. [0179] In some embodiments, the CSI report includes at least two CSI report parts, where the first of the two CSI report parts includes an indication of a total number of non-zero coefficients in the CSI report. In certain embodiments, the plurality of PM values consists of K PM values. In one embodiment, a second of the two CSI report parts includes K indicators of a respective per- PM number of coefficients corresponding to each of the K PM values. In another embodiment, a second of the two CSI report parts includes K-1 indicators of a respective per-PM number of coefficients corresponding to a first K-1 PM values of the K PM values. [0180] The memory 710, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 710 includes volatile computer storage media. For example, the memory 710 may include a RAM, including DRAM, SDRAM, and/or SRAM. In some embodiments, the memory 710 includes non-volatile computer storage media. For example, the memory 710 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 710 includes both volatile and non- volatile computer storage media. [0181] In some embodiments, the memory 710 stores data related to reporting phase- coupling coefficients with CSI. For example, the memory 710 may store parameters, configurations, and the like, as described above. In certain embodiments, the memory 710 also stores program code and related data, such as an operating system or other controller algorithms operating on the network apparatus 700. [0182] The input device 715, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 715 may be integrated with the output device 720, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device 715 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 715 includes two or more different devices, such as a keyboard and a touch panel. [0183] The output device 720, in one embodiment, is designed to output visual, audible, and/or haptic signals. In some embodiments, the output device 720 includes an electronically controllable display or display device capable of outputting visual data to a user. For example, the output device 720 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the output device 720 may include a wearable display separate from, but communicatively coupled to, the rest of the network apparatus 700, such as a smart watch, smart glasses, a heads-up display, or the like. Further, the output device 720 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like. [0184] In certain embodiments, the output device 720 includes one or more speakers for producing sound. For example, the output device 720 may produce an audible alert or notification (e.g., a beep or chime). In some embodiments, the output device 720 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the output device 720 may be integrated with the input device 715. For example, the input device 715 and output device 720 may form a touchscreen or similar touch-sensitive display. In other embodiments, the output device 720 may be located near the input device 715. [0185] The transceiver 725 includes at least one transmitter 730 and at least one receiver 735. One or more transmitters 730 may be used to communicate with the UE, as described herein. Similarly, one or more receivers 735 may be used to communicate with network functions in the PLMN and/or RAN, as described herein. Although only one transmitter 730 and one receiver 735 are illustrated, the network apparatus 700 may have any suitable number of transmitters 730 and receivers 735. Further, the transmitter(s) 730 and the receiver(s) 735 may be any suitable type of transmitters and receivers. [0186] Figure 8 illustrates a flowchart of a method 800 for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The operations of the method 800 may be implemented by a communication device, such as the remote unit 105, the UE 205, and/or the UE apparatus 600 (or components thereof), as described herein. Additionally, or alternatively, the operations of the method 800 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like. [0187] The method 800 includes receiving 805 a CSI reporting setting. The method 800 includes receiving 810, from at least one of a plurality of network nodes, a NZP CSI-RS associated with a CMR, where the CMR includes a plurality of CSI-RS partitions. The method 800 includes generating 815 a CSI report based on the CMR. Here, the CSI report includes A) a plurality of PM values corresponding to the plurality of CSI-RS partitions, B) one or more sets of phase- coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and C) an indication of a total number of coefficients of the plurality of PM values. The method 800 includes transmitting 820 the CSI report to at least one network node of the plurality of network nodes. [0188] Figure 9 illustrates a flowchart of a method 900 for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The operations of the method 900 may be implemented by a network entity, such as a base station unit 121, the RAN node 210, the TRP-1 303, the TRP-2305, the TRP-3307, the TRP-4309, and/or the network apparatus 700 (or components thereof), as described herein. Additionally, or alternatively, the operations of the method 900 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like. [0189] The method 900 includes transmitting 905 a CSI reporting setting. The method 900 includes transmitting 910 a NZP CSI-RS corresponding to a CMR, where the CMR is associated with a plurality of CSI-RS partitions. The method 900 includes receiving 915 a CSI report based on the CMR, where the CSI report includes: A) a plurality of PM values corresponding to the plurality of CSI-RS partitions, B) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and C) an indication of a total number of coefficients of the plurality of PM values. [0190] Disclosed herein is a first apparatus for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The first apparatus may be implemented by a communication device, such as the remote unit 105, the UE 205, and/or the UE apparatus 600, as described above. The first apparatus includes a processor coupled to a memory storing instructions executable by the processor to cause the first apparatus to: A) receive a CSI reporting setting; B) receive, from at least one of a plurality of network nodes, a NZP CSI-RS associated with a CMR, where the CMR includes a plurality of CSI-RS partitions; C) generate a CSI report based on the CMR, where the CSI report includes: i) a plurality of PM values corresponding to the plurality of CSI-RS partitions, ii) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and iii) an indication of a total number of coefficients of the plurality of PM values; and D) transmit the CSI report to at least one network node of the plurality of network nodes. [0191] In some embodiments, the plurality of PM values corresponds to one or more transmission hypotheses, where each transmission hypothesis corresponds to a coherent joint transmission from a set of the plurality of network nodes, and where each transmission hypothesis corresponds to a distinct subset of the set of phase coupling values. In certain embodiments, the one or more transmission hypotheses consists of K transmission hypotheses, where a respective PM value includes K-1 phase coupling coefficients, where K is a positive integer greater than one. [0192] In some embodiments, each network node of the plurality of network nodes is associated with a distinct CSI-RS partition of the plurality of CSI-RS partitions. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct NZP CSI-RS resource of the same NZP CSI-RS resource set. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct set of NZP CSI-RS ports. In certain embodiments, each distinct set of NZP CSI-RS ports corresponds to a distinct CDM group. [0193] In some embodiments, the plurality of CSI-RS partitions consists of K CSI-RS partitions, where the CSI report includes K subsets of phase coupling coefficients. In certain embodiments, each subset includes K-1 phase coupling coefficient values, where K is a positive integer greater than one having a value based on a number of the plurality of network nodes. In certain embodiments, the instructions are executable by the processor to cause the first apparatus to calculate each subset based on a network node with a fixed phase-coupling value. In one embodiment, the fixed phase-coupling value is set to zero. [0194] In some embodiments, the indication of the total number of coefficients of the plurality of PM values indicates a total amount of non-zero PM coefficients across all PM values included in the CSI report. In such embodiments, a number of phase-coupling coefficients in the one or more sets of phase-coupling coefficients is not included in the indication of the total number of coefficients. [0195] In some embodiments, the CSI report includes at least two CSI report parts, where the first of the two CSI report parts includes an indication of a total number of non-zero coefficients in the CSI report. In certain embodiments, the plurality of PM values consists of K PM values. In one embodiment, a second of the two CSI report parts includes K indicators of a respective per- PM number of coefficients corresponding to each of the K PM values. In another embodiment, a second of the two CSI report parts includes K-1 indicators of a respective per-PM number of coefficients corresponding to a first K-1 PM values of the K PM values. [0196] Disclosed herein is a first method for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The first method may be performed by a communication device, such as the remote unit 105, the UE 205, and/or the UE apparatus 600, as described above. The first method includes receiving a CSI reporting setting and receiving, from at least one of a plurality of network nodes, a NZP CSI-RS associated with a CMR, where the CMR includes a plurality of CSI-RS partitions. The first method includes generating a CSI report based on the CMR, where the CSI report includes: i) a plurality of PM values corresponding to the plurality of CSI-RS partitions, ii) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and iii) an indication of a total number of coefficients of the plurality of PM values. The first method includes transmitting the CSI report to at least one network node of the plurality of network nodes. [0197] In some embodiments, the plurality of PM values corresponds to one or more transmission hypotheses, where each transmission hypothesis corresponds to a coherent joint transmission from a set of the plurality of network nodes, and where each transmission hypothesis corresponds to a distinct subset of the set of phase coupling values. In certain embodiments, the one or more transmission hypotheses consists of K transmission hypotheses, where a respective PM value includes K-1 phase coupling coefficients, where K is a positive integer greater than one. [0198] In some embodiments, each network node of the plurality of network nodes is associated with a distinct CSI-RS partition of the plurality of CSI-RS partitions. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct NZP CSI-RS resource of the same NZP CSI-RS resource set. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct set of NZP CSI-RS ports. In certain embodiments, each distinct set of NZP CSI-RS ports corresponds to a distinct CDM group. [0199] In some embodiments, the plurality of CSI-RS partitions consists of K CSI-RS partitions, where the CSI report includes K subsets of phase coupling coefficients. In certain embodiments, each subset includes K-1 phase coupling coefficient values, where K is a positive integer greater than one having a value based on a number of the plurality of network nodes. In certain embodiments, the first method further includes calculating each subset based on a network node with a fixed phase-coupling value. In one embodiment, the fixed phase-coupling value is set to zero. [0200] In some embodiments, the indication of the total number of coefficients of the plurality of PM values indicates a total amount of non-zero PM coefficients across all PM values included in the CSI report. In such embodiments, a number of phase-coupling coefficients in the one or more sets of phase-coupling coefficients is not included in the indication of the total number of coefficients. [0201] In some embodiments, the CSI report includes at least two CSI report parts, where the first of the two CSI report parts includes an indication of a total number of non-zero coefficients in the CSI report. In certain embodiments, the plurality of PM values consists of K PM values. In one embodiment, a second of the two CSI report parts includes K indicators of a respective per- PM number of coefficients corresponding to each of the K PM values. In another embodiment, a second of the two CSI report parts includes K-1 indicators of a respective per-PM number of coefficients corresponding to a first K-1 PM values of the K PM values. [0202] Disclosed herein is a second apparatus for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The second apparatus may be implemented by a network entity, such as a base station unit 121, the RAN node 210, the TRP-1 303, the TRP-2305, the TRP-3307, the TRP-4309, and/or the network apparatus 700, as described above. The second apparatus includes a memory coupled to a processor, the memory including instructions executable by the processor to cause the second apparatus to: A) transmit a CSI reporting setting; B) transmit a NZP CSI-RS corresponding to a CMR, where the CMR is associated with a plurality of CSI-RS partitions; C) receive a CSI report based on the CMR, where the CSI report includes: i) a plurality of PM values corresponding to the plurality of CSI-RS partitions, ii) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and iii) an indication of a total number of coefficients of the plurality of PM values. [0203] In some embodiments, the plurality of CSI-RS partitions is associated with a plurality of network nodes and the plurality of PM values corresponds to one or more transmission hypotheses. In such embodiments, each transmission hypothesis corresponds to a coherent joint transmission from a set of the plurality of network nodes, where each transmission hypothesis corresponds to a distinct subset of the set of phase coupling values. In certain embodiments, the one or more transmission hypotheses consists of K transmission hypotheses, where a respective PM value includes K-1 phase coupling coefficients, where K is a positive integer greater than one. [0204] In some embodiments, the plurality of CSI-RS partitions is associated with a plurality of network nodes, where each network node of the plurality of network nodes is associated with a distinct CSI-RS partition of the plurality of CSI-RS partitions. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct NZP CSI-RS resource of the same NZP CSI-RS resource set. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct set of NZP CSI-RS ports. In certain embodiments, each distinct set of NZP CSI-RS ports corresponds to a distinct CDM group. [0205] In some embodiments, the plurality of CSI-RS partitions is associated with the plurality of network nodes, where the plurality of CSI-RS partitions consists of K CSI-RS partitions, and where the CSI report includes K subsets of phase coupling coefficients. In certain embodiments, each subset includes K-1 phase coupling coefficient values, where K is a positive integer greater than one having a value based on a number of a plurality of network nodes. In certain embodiments, the instructions are executable by the processor to cause the first apparatus to calculate each subset based on a network node with a fixed phase-coupling value. In one embodiment, the fixed phase-coupling value is set to zero. [0206] In some embodiments, the indication of the total number of coefficients of the plurality of PM values indicates a total amount of non-zero PM coefficients across all PM values included in the CSI report. In such embodiments, a number of phase-coupling coefficients in the one or more sets of phase-coupling coefficients is not included in the indication of the total number of coefficients. [0207] In some embodiments, the CSI report includes at least two CSI report parts, where the first of the two CSI report parts includes an indication of a total number of non-zero coefficients in the CSI report. In certain embodiments, the plurality of PM values consists of K PM values. In one embodiment, a second of the two CSI report parts includes K indicators of a respective per- PM number of coefficients corresponding to each of the K PM values. In another embodiment, a second of the two CSI report parts includes K-1 indicators of a respective per-PM number of coefficients corresponding to a first K-1 PM values of the K PM values. [0208] Disclosed herein is a second method for reporting phase-coupling coefficients with CSI, in accordance with aspects of the present disclosure. The second method may be performed by a network entity, such as a base station unit 121, the RAN node 210, the TRP-1303, the TRP- 2305, the TRP-3307, the TRP-4309, and/or the network apparatus 700, as described above. The second method includes transmitting a CSI reporting setting and transmitting a NZP CSI-RS corresponding to a CMR, where the CMR is associated with a plurality of CSI-RS partitions. The second method includes receiving a CSI report based on the CMR, where the CSI report includes: i) a plurality of PM values corresponding to the plurality of CSI-RS partitions, ii) one or more sets of phase-coupling coefficients based on a reference phase value, each set of phase-coupling coefficients being associated with a PM value of the plurality of PM values, and iii) an indication of a total number of coefficients of the plurality of PM values. [0209] In some embodiments, the plurality of CSI-RS partitions is associated with a plurality of network nodes and the plurality of PM values corresponds to one or more transmission hypotheses. In such embodiments, each transmission hypothesis corresponds to a coherent joint transmission from a set of the plurality of network nodes, where each transmission hypothesis corresponds to a distinct subset of the set of phase coupling values. In certain embodiments, the one or more transmission hypotheses consists of K transmission hypotheses, where a respective PM value includes K-1 phase coupling coefficients, where K is a positive integer greater than one. [0210] In some embodiments, the plurality of CSI-RS partitions is associated with a plurality of network nodes, where each network node of the plurality of network nodes is associated with a distinct CSI-RS partition of the plurality of CSI-RS partitions. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct NZP CSI-RS resource of the same NZP CSI-RS resource set. In some embodiments, each CSI-RS partition of the plurality of CSI-RS partitions includes a distinct set of NZP CSI-RS ports. In certain embodiments, each distinct set of NZP CSI-RS ports corresponds to a distinct CDM group. [0211] In some embodiments, the plurality of CSI-RS partitions is associated with the plurality of network nodes, where the plurality of CSI-RS partitions consists of K CSI-RS partitions, and where the CSI report includes K subsets of phase coupling coefficients. In certain embodiments, each subset includes K-1 phase coupling coefficient values, where K is a positive integer greater than one having a value based on a number of a plurality of network nodes. In certain embodiments, the instructions are executable by the processor to cause the first apparatus to calculate each subset based on a network node with a fixed phase-coupling value. In one embodiment, the fixed phase-coupling value is set to zero. [0212] In some embodiments, the indication of the total number of coefficients of the plurality of PM values indicates a total amount of non-zero PM coefficients across all PM values included in the CSI report. In such embodiments, a number of phase-coupling coefficients in the one or more sets of phase-coupling coefficients is not included in the indication of the total number of coefficients. [0213] In some embodiments, the CSI report includes at least two CSI report parts, where the first of the two CSI report parts includes an indication of a total number of non-zero coefficients in the CSI report. In certain embodiments, the plurality of PM values consists of K PM values. In one embodiment, a second of the two CSI report parts includes K indicators of a respective per- PM number of coefficients corresponding to each of the K PM values. In another embodiment, a second of the two CSI report parts includes K-1 indicators of a respective per-PM number of coefficients corresponding to a first K-1 PM values of the K PM values. [0214] Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. [0215] As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects. [0216] For example, the disclosed embodiments may be implemented as a hardware circuit comprising custom very-large-scale integration (“VLSI”) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. The disclosed embodiments may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. [0217] Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non- transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code. [0218] Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. [0219] More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a RAM, a read-only memory (“ROM”), an erasable programmable read-only memory (“EPROM”), an electronically erasable programmable read-only memory (“EEPROM”), a Flash memory, a portable compact disc read-only memory (“CD-ROM”), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device. [0220] Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object- oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the “C” programming language, or the like, and/or machine languages such as assembly languages. The code may execute entirely on the user’s computer, partly on the user’s computer, as a stand-alone software package, partly on the user’s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user’s computer through any type of network, including a local area network (“LAN”), WLAN, or a wide area network (“WAN”), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider (“ISP”)). [0221] Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment. [0222] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to,” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise. [0223] As used herein, a list with a conjunction of “and/or” includes any single item in the list or a combination of items in the list. For example, a list of A, B and/or C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one or more of” includes any single item in the list or a combination of items in the list. For example, one or more of A, B and C includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, a list using the terminology “one of” includes one and only one of any single item in the list. For example, “one of A, B and C” includes only A, only B or only C and excludes combinations of A, B and C. As used herein, “at least one of A, B and C” includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. As used herein, “a member selected from the group consisting of A, B, and C,” includes one and only one of A, B, or C, and excludes combinations of A, B, and C. As used herein, “a member selected from the group consisting of A, B, and C and combinations thereof” includes only A, only B, only C, a combination of A and B, a combination of B and C, a combination of A and C or a combination of A, B and C. [0224] Aspects of the embodiments are described above with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. This code may be provided to a processor of a general-purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart diagrams and/or block diagrams. [0225] The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the flowchart diagrams and/or block diagrams. [0226] The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart diagrams and/or block diagrams. [0227] The call-flow diagrams, flowchart diagrams and/or block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods, and program products according to various embodiments. In this regard, each block in the flowchart diagrams and/or block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function(s). [0228] It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures. [0229] Although various arrow types and line types may be employed in the call-flow, flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code. [0230] The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.